Internal combustion engine control system with means for reshaping of command from driver's foot pedal

Abstract

An electronic control fuel injection system for a spark ignition internal combustion engine is described wherein air flow rate is controlled as a function of fuel flow rate by transmitting an operator's depression stroke of an accelerator pedal to a fuel selecting mechanism, applying a signal representative of the selected fuel flow rate to a computer which determines the optimum air flow rate, thereby controlling the opening of a throttle valve to provide it. Within the computer, the relationship of the accelerator pedal movement to actual fuel flow command is varied in a predetermined manner to provide a desired engine response characteristic. Thus, the drive feeling for a vehicle can be varied within a range from normal to either a faster or more conservative engine reaction.

We claim: 
     
       1. An electronic control fuel injection system for a spark ignition internal combustion engine having a throttle valve for preferentially determining fuel flow rate and subordinately determining air flow rate to the engine in response to the fuel flow rate and the engine operating state comprising: an accelerator pedal having a stroke from an idle position to a maximum position;   fuel command means driven by said pedal for producing a fuel command signal varying in accordance with a non-linear mathematical function of the distance of said pedal from its idle position and derivatives or differences of said distance with respect to time;   reshaping means for selecting a particular said non-linear function;   fuel metering means for discharging the fuel in accordance with the command from said fuel command means;   at least one fuel injector for injecting said fuel discharge amount into said engine;   intake air flow sensing means for detecting the amount of intake air to said engine;   computing means for selectively receiving output signals from said fuel metering means indicating said fuel discharge amount and output signals from said intake air flow sensing means indicating actual air flow, and calculating an optimum air supply amount, and   throttle valve servo means for determining the openng of said throttle valve according to the output from said computing means to provide said optimum air supply amount to said engine.   
     
     
       2. An electronic control fuel injection system for a spark ignition internal combustion engine having a throttle valve for preferentially determining fuel flow rate and subordinately determining air flow rate to the engine in response to the fuel flow rate and the engine operating state, comprising: an accelerator pedal having a stroke from an idle position to a maximum position;   encoder means for generating an accelerator position signal;   fuel command means driven by said encoder means for producing a fuel command signal varying in accordance with a particular non-linear mathematical function of the distance of said pedal from its idle position;   at least one fuel injector for injecting said fuel discharge amount into said engine and having fuel metering means for discharging the fuel in accordance with said fuel command signal;   calculator means for initially calculating a raw, uncorrected desired air flow rate A r  corresponding to optimum air flow for each fuel flow value as delivered by said fuel metering means, and for later calculating corrected values;   temperature detecting means for detecting engine temperature and transmitting its value to said calculation means for calculating a corrected desired air flow rate A d  ;   air flow sensing means for detecting the actual amount of intake air A a  being supplied to said engine at each instant;   subtracting means for subtracting continuously the value A a  from A d  and generating a difference signal therefrom, and   throttle valve servo means driven by said difference signal for varying the opening of said throttle valve to move the difference toward zero to provide said optimum air supply amount to said engine.   
     
     
       3. An electronic control fuel injection system for a spark ignition internal combustion engine having a throttle valve for preferentially determining fuel flow rate and subordinately determining air flow rate to the engine in response to the fuel flow rate and the engine operating state, comprising: an accelerator pedal having a stroke from an idle position to a maximum position,   encoder means for generating an accelerator position signal,   fuel command means driven by said encoder means for producing a fuel command signal varying in accordance with a particular mathematical function of the distance of said pedal from its idle position,   at least one fuel injector for injecting said fuel discharge amount into said engine and having fuel metering means for discharging the fuel in accordance with said fuel command signal;   calculator means for initially calculating a raw, uncorrected desired air flow rate A r  corresponding to optimum air flow for each fuel flow value as delivered by said fuel metering means, and for later calculating corrected values,   temperature detecting means for detecting engine temperature and transmitting its value to said calculation means for calculating a corrected desired air flow rate A d ,   a second temperature sensing means for sensing ambient atmospheric temperature and sending the second value to said calculator means to refine the value A d ,   pressure sensing means for sensing ambient atmospheric pressure and sending the second value to said calculator means to refine further the value A d ,   air flow sensing means for detecting the actual amount of intake air A a  being supplied to said engine at each instant,   subtracting means for for subtracting continuously the value A a  from A d  and generating a difference signal therefrom, and   throttle valve servo means driven by said difference signal for varying the opening of said throttle valve to move the difference toward zero to provide said optimum air supply amount to said engine.   
     
     
       4. The system of claim 1 wherein said reshaping means selects said function from the powers 1/2, and 2. 
     
     
       5. The system of claim 1 wherein said fuel command means includes as part thereof a portion of said computing means. 
     
     
       6. The system of claim 3 having reshaping means for changing one said particular mathematical funtion to a different particular mathematical function. 
     
     
       7. The system of claim 2 having reshaping means for changing one said particular mathematical funtion to a different particular mathematic funtion.